Alternative Names: Cholesteatoma.
Definition: A cyst is an epithelial layer on the outside filled with the products that the epithelial layer can produce. A benign ear tumor can be any growth arising from tissues in the external ear canal, the eardrum, or the middle ear space.
What Is Going on in My Body? The most common type of benign ear cyst is a cholesteatoma (also known as keratoma). A cholesteatoma is a cyst that forms usually in the middle ear (the space behind the eardrum). There are several ways that a cholesteatoma can form. They can result from remnants of skin in the middle ear left over from the embryologic process of middle ear development and are, therefore, termed congenital cholesteatomas. They typically arise in the upper, most forward portion of the middle ear space. Another way that cholesteatoma forms is from a retraction pocket arising from the tympanic membrane (eardrum). A retraction pocket forms when the eustachian tube that normally drains the ear into the back part of the nasal cavity does not function well, and a vacuum develops behind the drum. This vacuum then starts to pull the eardrum inward, and if this process continues long enough, pockets or pouches can form from it. The outer layer of the tympanic membrane is a very thin layer of skin. As this pocket or pouch continues to enlarge, the skin lining of the pocket has more difficulty getting rid of the dead skin, and therefore, it starts to accumulate. As it accumulates within the pouch, it can get infected or can start to erode some of the bony structures in the middle ear, such as the ossicles or the bony structure (cochlea) that houses the inner ear or the bony covering of the facial nerve. Another way in which a cholesteatoma can form is if there is a hole in the eardrum (perforation). This is particularly likely if the edge of the hole is in contact with the outer ear canal. The skin that lines the ear canal or the eardrum can then grow through the perforation into the middle ear and then the enlarging mass of skin can accumulate, creating the same problem mentioned above for a retraction pocket cholesteatoma. Lastly, it is also thought that chronic inflammation in the middle ear can lead to cholesteatoma. With chronic inflammation of any mucous membrane surface it can start to change into a lining more similar to skin. If this transformation becomes complete, then skin can replace areas of the normal mucous membrane behind the eardrum. Since the shedding skin is then trapped behind the eardrum, the skin continues to accumulate and can result in infection or destruction of middle ear structures. One of the main causes of cholesteatoma formation is a eustachian tube that does not function well. Eustachian tube problems tend to run in families or certain ethnic groups, such as Eskimos or individuals of American Indian descent. Other disorders, such as cleft palate, Down’s syndrome, or other craniofacial abnormalities that impair eustachian tube function may also have a higher frequency of cholesteatoma formation.
For those benign ear tumors that are not cholesteatoma, they can arise from any of the tissues that form the ear structures. This could include the skin of the outer ear canal or the oil or ear wax glands. Tumors arising from a mucous membrane surface could develop in the middle ear space.
What Are the Signs and Symptoms? For cholesteatomas often there is a history of difficulty with eustachian tube function, so that there may have been frequent ear infections in the past. The most common symptom of a hematoma is gradual decline in hearing. These individuals often have an ear that drains infected material out of the ear canal on an intermittent basis. This would be mostly true for those patients who have retraction pocket or perforation-related cholesteatomas. The individual with congenital hearing cholesteatoma will mostly demonstrate progressively declining hearing. Symptoms of great concern in an individual with hearing loss and ear drainage would be facial paralysis or vertigo. These symptoms would be an indication of erosion through the bony canal housing the facial nerve or the bony boundary of the inner ear, respectively. Prior to the employment of antibiotics and improved access to health care, cholesteatomas were complicated by meningitis, brain abscess, or epidural abscess with a subsequent high morbidity and mortality rate.
For the individual who has a benign ear tumor, if it is behind the tympanic membrane the main symptom would be hearing loss as it began to impair eardrum or middle ear bone function. If the tumor is in the ear canal, hearing loss is a common symptom, but these individuals might also have difficulties with frequent infections of the skin in the outer ear canal (acute otitis externa).
What Are the Causes and Risks? As mentioned previously, the main cause of cholesteatoma would be congenital, retraction pockets consequent to eustachian tube dysfunction, or tympanic membrane perforation, often a result of eustachian tube dysfunction, previous ventilation tube placement, or trauma. Lastly, chronic middle ear disease may also increase the risk of cholesteatoma formation. As discussed previously, other factors that would cause a poorly functioning eustachian tube and place a patient at risk are cleft palate, Down’s syndrome, craniofacial abnormality, or Eskimo/American Indian descent. One other group deserves special mention. Welders who get slag burns of the eardrum have a fairly high risk of cholesteatoma formation.
How to Prevent the Disease: For those individuals who have it form congenitally, there is no preventive mechanism. Patients who suffer from significant eustachian tube dysfunction need to have its performance maximized or bypassed either with management of the underlying medical disease that leads to tube dysfunction, such as adenoidal hypertrophy, allergy, a chronic sinusitis, or ventilation tube (pressure equalization) placement. For those patients with retraction pockets that continue to enlarge but have not yet formed a cholesteatoma, ventilation tubes will often arrest this process of worsening drum retraction. Treating recurrent ear infections and regular well child visits which would identify silent ear disease in the form of retracted tympanic membrane or fluid behind the ear are important.
The only type of benign ear tumor that is really preventable is a benign bony tumor (osteoma) that can form in the ear canal of individuals who frequently swim, surfboard, windsurf, or water ski. For some reason, individuals heavily involved in water sports suffer from benign bone growths forming in the ear canal. If these get large enough, they can impair the hearing and prevent water from exiting the ear canal and thus lead to recurrent external ear infections.
How Is It Diagnosed? For those benign ear tumors arising in the ear canal or the middle ear, examination of the ear canal and the middle ear can often identify the tumor. To determine its exact nature, a biopsy is often required. Hearing tests help quantify the degree of hearing loss and determine whether or not it is from nerve dysfunction, or impairment of sound getting through the eardrum or the bones for hearing. A CT scan may be necessary to determine the extent of a benign ear tumor to help plan its surgical removal.
Cholesteatomas are often easily diagnosed by examining the external ear canal and the eardrum. Retraction pockets are quite easy to identify, as are eardrum perforations. Whitish, waxy material in a retraction pocket or visible through the perforation would definitely herald a cholesteatoma. Individuals who have congenital cholesteatoma often have a whitish, waxy, and slightly red mass seen through an intact eardrum, usually in the front part of the middle ear space. If the eardrum does not have a hole in it or a retraction pocket, the eardrum may appear a very bright white as opposed to its more normal wax-paper-like appearance. The white appearance can indicate a cholesteatoma. To determine the degree of the hearing loss, your physician may obtain a hearing test, and certainly for cholesteatomas a CT scan or mastoid x-rays are very important to try to determine the extent of the cholesteatoma and what important structures it might be affecting.
What Are the Long-Term Effects: The major long-term effect of a benign ear tumor would be hearing loss if it were not treated. As mentioned before, bony ear canal tumors, when quite large, can cause recurrent outer ear canal infections. Otherwise there are no significant long-term problems.
Major long-term effects for a cholesteatoma can be recurrent ear infections and hearing loss. Certainly an untreated cholesteatoma that continues to expand places the individual at risk for facial nerve paralysis, loss of inner ear balance and hearing function with profound deafness and potentially spread of the infection into the cranial cavity.
Am I Putting Others at Risk? No, other than any problem that might arise from not being able to hear.
What Are the Treatments? For an asymptomatic benign ear tumor, observation maybe all that is necessary. Surgical removal would be employed if hearing loss or ear canal infections were to occur.
Treatment for a cholesteatoma requires surgery. If they are particularly small, such as an early identified congenital cholesteatoma, they can be removed by going through the ear canal, lifting up the eardrum, and shelling out the cholesteatoma. For more extensive cholesteatomas, opening up the mastoid (the bone which houses a honeycomb-like air-filled chamber that communicates directly with the space behind the eardrum) may be necessary, along with lifting up the eardrum to completely remove it. If there are holes in the eardrum or problems with the bones for hearing, these can be repaired simultaneously. Unfortunately, cholesteatomas have a 30 to 50% recurrence rate, so the surgeon may recommend a repeat exploration of the middle ear and/or mastoid at six to nine months after the original surgery. There are also occasions where the middle ear cannot be reconstructed at the time of the original operation; and, therefore, reconstruction may also be performed at a later date.
What Are the Side Effects to the Treatments? The major side effects of the treatment would be that typical with any surgical procedure, such as pain, infection, or bleeding. Any time there is surgery performed on the eardrum, the bones for hearing, or the mastoid, there can be damage to any or all of these structures. Fortunately, major complications are quite infrequent. Main complications could include reperforation of a repaired eardrum, hearing loss either from problems of sound transmission through the reconstructed eardrum or bones for hearing, or even deafness. Since the inner ear is also involved in balance function, dizziness can be a complication of surgical treatment. There is a rare but definite risk of facial nerve paralysis if the facial nerve is injured during surgical procedures. There is also a small nerve that goes through the middle ear between the incus and malleus that relays taste information from the front part of the tongue; and, therefore, taste disturbance can occur after any kind of middle ear surgery.
What Happens After Treatment? For removal of benign ear canal tumors, antibiotic and steroid ear drops are often necessary to allow the ear canal skin to heal. If benign tumors are removed from the eardrum or the middle ear space, the ear canal is often packed with dissolvable materials and ointments. This may require several visits to your surgeon to have this material removed and to monitor healing. It is very common to obtain a hearing test two to three months post-operatively to determine the state of the hearing. For those individuals who have had a cholesteatoma, in addition to what was just mentioned, an exploratory procedure six to nine months after the original procedure may be recommended to try to identify any cholesteatoma recurrence. Individuals with cholesteatomas, because they can recur, often need extended periods of follow-up to ensure that in fact they do not return.
How Do I Monitor the Disease? Once a benign ear canal or middle ear tumor is removed and the hearing is stable, usually no further treatment is necessary. Individuals suffering with cholesteatoma, because they can recur, in the event of early identification of any of the symptoms, such as hearing loss or ear drainage, must notify their physician immediately.